Figure 3

Ontology of clinical trials data project. User-defined ontology of the clinical trials data project in the Department of Gastrointestinal Medical Oncology, MD Anderson Cancer Center. The user describes the ontology by defining "rules," which in turn are instantiated by "statements." The oval node represents the root of the ontology; the red nodes represent rule elements that are collections of items; the green nodes represent rule objects that take literal values.